This is currently all the gear I have for gathering specimens in and around the waters I fish, and have a bad tendency to leave the net back at the car. What equipment do you use, if any at all to gather insects stream-side for closer study at home?

Ya small nets can be a bummer, but a larger aquatic sampling net would be much better. The long cone and fine mesh helps keep mud out and bugs in. all u need to do is disrupt the bottom upstream form the net so everything flows into the net and u got bugs. theirs also jabbing that can be done these tend to get larger bugs and crawfish. a simple water bottle and some sort of mesh like pan or prospectoring pan to filter out rocks and such. lastly use a light and a glass pan to allow for better viewing of what you got. After all of that you just need a good id key for both adult and juvie inverts. I did this for a job for a few years and this is about the simplest way to get the best results. 70% isopropal for preserving anything you wish to keep.